|Titre||The Lomonosov Ridge stable position during the opening of the Arctic Ocean|
|Auteur||Jackson, H R; Funck, T; Hell, B|
|Séries alt.||Secteur des sciences de la Terre, Contribution externe 20110133|
|Réunion||International conference on Arctic Margins (ICAM6)|
|Programme||Preparation of a submission for an extended continental shelf in the Atlantic and Arctic Oceans under UNCLOS, Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies
sur le droit de la mer (UNCLOS)|
|Résumé||(disponible en anglais seulement)|
The Lomonosov Ridge crosses the Arctic Ocean from north of Ellesmere Island and Greenland to near the New Siberian Islands. The position of the ridge adjacent
to its North American termination is constrained by the onshore circum-Arctic geology and substantiated by offshore geophysical data. The earliest geological event that indicates its location occurred in the Late Devonian-Early Carboniferous. The
docking of continental block, presumably derived from Baltica that some authors believe to be Svalbard, against Ellesmere Island caused the Innuitian (Ellesmerian) Orogeny. It has been postulated that this event created the core of the Lomonosov
Ridge. Through the Late Paleozoic to Mesozoic close stratigraphic ties with the Sverdrup Basin (on the Canadian Arctic Islands), Svalbard and Franz Josef Land are well documented. The Lincoln Sea basin, whose architecture is defined using refraction
results, provides a link between diverse areas in the Arctic prior to seafloor spreading. Comparison of refraction profiles from Franz Josef Land and the Lomonosov Ridge near the pole show similarities, supporting the close proximity of the ridge to
the Kara Sea margin. The location of the Lomonosov Ridge is also constrained by a radiating dyke swarm that originates on the plateau of the Lomonosov Ridge adjacent Canada and Greenland that can be traced to Svalbard and Franz Josef Land. The age of
the 350 km wide dyke swarm on Franz Josef Land, and dykes on Svalbard are not tightly constrained but are sufficient to determine the ridge's position in the Early Cretaceous.
The Lomonosov Ridge's stable position and narrow width in the Arctic
Ocean mean that the stratigraphy of archipelagos of Franz Josef Land and Svalbard are useful in deterring the age of opening of the Canada Basin. Svalbard has a continuous record of sedimentation with accumulation occurring from the late Paleozoic to
Mesozoic. Surprisingly, the stratigraphic record was interrupted in the Cretaceous when there was a worldwide high stand of sea level. This non depositional event is postulated to be caused by the opening of the Amerasia Basin. The stratigraphy on
Franz Josef Land has also recorded this event and is less likely to have been influenced by the opening of the North Atlantic at a later date. The age of the break up unconformity from Franz Josef Land, Svalbard and the Canadian Arctic Islands is
The Lomonosov Ridge has been called a two-sided continental margin. The Eurasia Basin margin is a rifted margin with seafloor spreading occurring as early as anomaly 25. Prior to that anomaly the Lomonosov Ridge was part of the margin
of Barents and Kara seas. The sedimentary sequence on the Makarov Basin side of the Lomonosov Ridge near the North Pole is thicker than at the margins. The sedimentary distribution is consistent with this portion of the Lomonosov Ridge lying adjacent
the St Anna Trough on the Kara Sea margin during the opening of the Canada Basin. It has been suggested that the Makarov Basin margin has been either a rifted or a transform margin.
The Lomonosov Ridge divides the Arctic Ocean into two major
basins, is a double sided continental margin and its position has been stable relative to Canadian Arctic Islands since the Innuitian Orogeny.